1) Field of the Invention
Present invention relates generally to seeding implements such as planters and drills and to the devices for closing the seed trench behind seed planters and seed drills.
2) Related Art
Proper seed placement in the furrows opened for the seeds by grain drills and planters has been the subject of many inventions. The closing devices for closing the furrows or trenches have not been the subject of much change and consist of mainly round wheels which are of smooth contour and generally made of rubber or steel. These wheels have generally been placed at an angle to the furrow and have tried to push the soil from the side and move the soil back to close the furrow by pressure. The squeezing action of the seed trench opening discs produces a very tightly compacted side wall which is under normal circumstances pressured by the closing wheels to close the furrow. The pressure on the tightly compacted soil causes further compaction with resultant poor germination and emergence.
The normal smooth closing wheels are not engaged in the soil and on slopes or contour may shift into either a position in the trench or sufficiently removed from the seed trench that inadequate furrow closing results.
Various devices have recently been devised to attempt to improve the closing of the seed trench. This includes a tined or spoked wheel configuration which is designed to be an improvement over the smooth wheels. These spoked wheels have been fitted to planters to replace the smooth round closing wheels. The prior art closing, spoked or tined wheels operate to apply alternate pressure to the soil in a manner similar to the round wheels, but do not have as much pressure applied. The tined wheels are arranged to operate so that the tines are in the least aggressive position with regard to the soil near the seed furrow trench. The tines are designed in this mode not to penetrate the soil, but rather to kick or flip out the back any trash that may be left on the surface. The design of these prior art wheels is such that when operated in a mode opposite the hoeing mode they have an action similar to a raking motion. The tines cause a very shallow disturbance of the soil as the wheels rotate.
Prior closing devices for seed furrow trenches have always been designed so that they will not cultivate the soil near the seed because of fear of moving the seed rather than covering the seed. These devices have been designed to close the furrow either by pressure or by shallow disturbance of the soil to create a covering of the soil over the seed.
Although providing some improvement in crop emergence these devices have not provided the elimination of compaction of the soil around the seed or provided adequate penetration above the seed. The compacted side wail of the trench formed by the disc opener and closed by smooth wheels can result in hardened soil surfaces either with rainfall or without rainfall. The seed is not under the ideal germination conditions, i.e. firmly placed in soil at proper depth with well mulched soil around it to permit its proper emergence regardless of whether or not there is rainfall. This is particularly true in minimum tillage, high residue operations in which the closing device of this invention operates most efficiently.